The present invention relates generally to integrated frame systems, and more particularly to an integrated frame system for a clamping frame of a transformer core.
As a rule, transformers, particularly power transformers, contain a transformer core formed by a stack of core laminations. The coils of the individual phases are configured on the leg of this transformer core. The coils can be encapsulated in casting resin. The part of the transformer core, e.g. yokes and legs, are held together by a clamping frame. The clamping frame consists of frame parts, in particular metal sections on both sides of the yokes, which are screwed to one another through the laminations. In addition, the frame parts of two transformer yokes are connected to one another by means of tensioners. The purpose of these tensioners is to brace the transformer along its leg and to affix the coils to the legs.
Trafo-Union publication A 19100-T1306-A13, page 3, illustration 2 discloses and illustrates in detail such a transformer. In particular, the exact construction of the clamping frame is shown. The tensioners consist of a metal band, which has a bolt that is supported in the frame part, at least at one end. A bolthead of an eye-bolt engages with this bolt and is secured by a clamping nut to the frame part. The clamping nut is used to adjust the tensile force at the tie-bolt. Separate tie-bolts are provided on both sides for each leg. In this manner, the frame pans of the clamping frame can be braced together with the core and the coils. The grid system between the tensioners and frame bars is costly, because many individual parts are needed. Producing the grid system is both labor and cost intensive.
GB-A-1 121 993 discloses a clamping frame in which the tensioner rests directly on one leg of the core and overlaps the frame parts in the vicinity of the yoke. In this variant, there is an unfavorable force control because of the tensioner, whereby tensioning the tensioner can cause it to lift off the leg. In addition, the tensioner is expensive to produce.
Thus, there is a need to develop an integrated frame system that requires less labor and cost to construct.